Polarizing plates are widely used as an element to generate polarization and as an element to detect polarization in a liquid crystal display device. Such polarizing plates in which a protective film composed of triacetylcellulose or the like is adhered to one surface or both surfaces of a polarizing film composed of a polyvinyl alcohol resin are conventionally used. Decrease in thickness and weight of polarizing plates has been recently requested in association with the increasing application of liquid crystal display devices to mobile devices such as notebook type personal computers and cellular phones, and further to large size televisions.
For example, JP 2000-338329-A, JP 2009-93074-A, JP 2009-98653-A and JP 2003-43257-A disclose a method for production of a polarizing plate by the use of a stretched film obtained by stretching a resin layer of polyvinyl alcohol resin formed on one surface of a base film comprising a single resin layer, as a method for producing a thin polarizing plate.
In producing a polarizing plate using the conventional stretched film as described-above, however, particularly if the draw ratio of the stretched film used is high, there is a problem of tearing of the film to the stretching direction when rolls, such as nip rolls, wind the film in dying the polyvinyl alcohol resin layer.
An object of the present invention is to provide a stretched film with a uniaxially stretched polyvinyl alcohol resin layer formed on one surface of a base film, the tearing of which to the stretching direction can be successfully restrained in a dying step of producing a polarizing plate or a polarizing stretched film. Another object of the present invention is to provide a polarizing stretched film and a polarizing plate by the use of the polarizing stretched film to which polarizing performance has been imparted.